<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package		CodeIgniter
 * @author		ExpressionEngine Dev Team
 * @copyright	Copyright (c) 2008 - 2009, EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 1.0
 * @filesource
 */

// ------------------------------------------------------------------------

/**
 * Typography Class
 *
 *
 * @access		private
 * @category	Helpers
 * @author		ExpressionEngine Dev Team
 * @link		http://codeigniter.com/user_guide/helpers/
 */
class CI_Typography {

// Block level elements that should not be wrapped inside <p> tags
  var $block_elements = 'address|blockquote|div|dl|fieldset|form|h\d|hr|noscript|object|ol|p|pre|script|table|ul';

  // Elements that should not have <p> and <br /> tags within them.
  var $skip_elements	= 'p|pre|ol|ul|dl|object|table|h\d';

  // Tags we want the parser to completely ignore when splitting the string.
  var $inline_elements = 'a|abbr|acronym|b|bdo|big|br|button|cite|code|del|dfn|em|i|img|ins|input|label|map|kbd|q|samp|select|small|span|strong|sub|sup|textarea|tt|var';

  // array of block level elements that require inner content to be within another block level element
  var $inner_block_required = array('blockquote');

  // the last block element parsed
  var $last_block_element = '';

  // whether or not to protect quotes within { curly braces }
  var $protect_braced_quotes = FALSE;

  /**
   * Nothing to do here...
   *
   */
  function CI_Typography() {
  }

  /**
   * Auto Typography
   *
   * This function converts text, making it typographically correct:
   * 	- Converts double spaces into paragraphs.
   * 	- Converts single line breaks into <br /> tags
   * 	- Converts single and double quotes into correctly facing curly quote entities.
   * 	- Converts three dots into ellipsis.
   * 	- Converts double dashes into em-dashes.
   *  - Converts two spaces into entities
   *
   * @access	public
   * @param	string
   * @param	bool	whether to reduce more then two consecutive newlines to two
   * @return	string
   */
  function auto_typography($str, $reduce_linebreaks = FALSE) {
    if ($str == '') {
      return '';
    }

    // Standardize Newlines to make matching easier
    if (strpos($str, "\r") !== FALSE) {
      $str = str_replace(array("\r\n", "\r"), "\n", $str);
    }

    // Reduce line breaks.  If there are more than two consecutive linebreaks
    // we'll compress them down to a maximum of two since there's no benefit to more.
    if ($reduce_linebreaks === TRUE) {
      $str = preg_replace("/\n\n+/", "\n\n", $str);
    }

    // HTML comment tags don't conform to patterns of normal tags, so pull them out separately, only if needed
    $html_comments = array();
    if (strpos($str, '<!--') !== FALSE) {
      if (preg_match_all("#(<!\-\-.*?\-\->)#s", $str, $matches)) {
        for ($i = 0, $total = count($matches[0]); $i < $total; $i++) {
          $html_comments[] = $matches[0][$i];
          $str = str_replace($matches[0][$i], '{@HC'.$i.'}', $str);
        }
      }
    }

    // match and yank <pre> tags if they exist.  It's cheaper to do this separately since most content will
    // not contain <pre> tags, and it keeps the PCRE patterns below simpler and faster
    if (strpos($str, '<pre') !== FALSE) {
      $str = preg_replace_callback("#<pre.*?>.*?</pre>#si", array($this, '_protect_characters'), $str);
    }

    // Convert quotes within tags to temporary markers.
    $str = preg_replace_callback("#<.+?>#si", array($this, '_protect_characters'), $str);

    // Do the same with braces if necessary
    if ($this->protect_braced_quotes === TRUE) {
      $str = preg_replace_callback("#\{.+?\}#si", array($this, '_protect_characters'), $str);
    }

    // Convert "ignore" tags to temporary marker.  The parser splits out the string at every tag
    // it encounters.  Certain inline tags, like image tags, links, span tags, etc. will be
    // adversely affected if they are split out so we'll convert the opening bracket < temporarily to: {@TAG}
    $str = preg_replace("#<(/*)(".$this->inline_elements.")([ >])#i", "{@TAG}\\1\\2\\3", $str);

    // Split the string at every tag.  This expression creates an array with this prototype:
    //
    // 	[array]
    // 	{
    // 		[0] = <opening tag>
    // 		[1] = Content...
    // 		[2] = <closing tag>
    // 		Etc...
    // 	}
    $chunks = preg_split('/(<(?:[^<>]+(?:"[^"]*"|\'[^\']*\')?)+>)/', $str, -1, PREG_SPLIT_DELIM_CAPTURE|PREG_SPLIT_NO_EMPTY);

    // Build our finalized string.  We cycle through the array, skipping tags, and processing the contained text
    $str = '';
    $process = TRUE;
    $paragraph = FALSE;
    $current_chunk = 0;
    $total_chunks = count($chunks);

    foreach ($chunks as $chunk) {
      $current_chunk++;

      // Are we dealing with a tag? If so, we'll skip the processing for this cycle.
      // Well also set the "process" flag which allows us to skip <pre> tags and a few other things.
      if (preg_match("#<(/*)(".$this->block_elements.").*?>#", $chunk, $match)) {
        if (preg_match("#".$this->skip_elements."#", $match[2])) {
          $process =  ($match[1] == '/') ? TRUE : FALSE;
        }

        if ($match[1] == '') {
          $this->last_block_element = $match[2];
        }

        $str .= $chunk;
        continue;
      }

      if ($process == FALSE) {
        $str .= $chunk;
        continue;
      }

      //  Force a newline to make sure end tags get processed by _format_newlines()
      if ($current_chunk == $total_chunks) {
        $chunk .= "\n";
      }

      //  Convert Newlines into <p> and <br /> tags
      $str .= $this->_format_newlines($chunk);
    }

    // No opening block level tag?  Add it if needed.
    if ( ! preg_match("/^\s*<(?:".$this->block_elements.")/i", $str)) {
      $str = preg_replace("/^(.*?)<(".$this->block_elements.")/i", '<p>$1</p><$2', $str);
    }

    // Convert quotes, elipsis, em-dashes, non-breaking spaces, and ampersands
    $str = $this->format_characters($str);

    // restore HTML comments
    for ($i = 0, $total = count($html_comments); $i < $total; $i++) {
    // remove surrounding paragraph tags, but only if there's an opening paragraph tag
    // otherwise HTML comments at the ends of paragraphs will have the closing tag removed
    // if '<p>{@HC1}' then replace <p>{@HC1}</p> with the comment, else replace only {@HC1} with the comment
      $str = preg_replace('#(?(?=<p>\{@HC'.$i.'\})<p>\{@HC'.$i.'\}(\s*</p>)|\{@HC'.$i.'\})#s', $html_comments[$i], $str);
    }

    // Final clean up
    $table = array(

        // If the user submitted their own paragraph tags within the text
        // we will retain them instead of using our tags.
        '/(<p[^>*?]>)<p>/'		=> '$1', // <?php BBEdit syntax coloring bug fix

        // Reduce multiple instances of opening/closing paragraph tags to a single one
        '#(</p>)+#'			=> '</p>',
        '/(<p>\W*<p>)+/'	=> '<p>',

        // Clean up stray paragraph tags that appear before block level elements
        '#<p></p><('.$this->block_elements.')#'	=> '<$1',

        // Clean up stray non-breaking spaces preceeding block elements
        '#(&nbsp;\s*)+<('.$this->block_elements.')#'	=> '  <$2',

        // Replace the temporary markers we added earlier
        '/\{@TAG\}/'		=> '<',
        '/\{@DQ\}/'			=> '"',
        '/\{@SQ\}/'			=> "'",
        '/\{@DD\}/'			=> '--',
        '/\{@NBS\}/'		=> '  '

    );

    // Do we need to reduce empty lines?
    if ($reduce_linebreaks === TRUE) {
      $table['#<p>\n*</p>#'] = '';
    }
    else {
    // If we have empty paragraph tags we add a non-breaking space
    // otherwise most browsers won't treat them as true paragraphs
      $table['#<p></p>#'] = '<p>&nbsp;</p>';
    }

    return preg_replace(array_keys($table), $table, $str);

  }

  // --------------------------------------------------------------------

  /**
   * Format Characters
   *
   * This function mainly converts double and single quotes
   * to curly entities, but it also converts em-dashes,
   * double spaces, and ampersands
   *
   * @access	public
   * @param	string
   * @return	string
   */
  function format_characters($str) {
    static $table;

    if ( ! isset($table)) {
      $table = array(
          // nested smart quotes, opening and closing
          // note that rules for grammar (English) allow only for two levels deep
          // and that single quotes are _supposed_ to always be on the outside
          // but we'll accommodate both
          // Note that in all cases, whitespace is the primary determining factor
          // on which direction to curl, with non-word characters like punctuation
          // being a secondary factor only after whitespace is addressed.
          '/\'"(\s|$)/'					=> '&#8217;&#8221;$1',
          '/(^|\s|<p>)\'"/'				=> '$1&#8216;&#8220;',
          '/\'"(\W)/'						=> '&#8217;&#8221;$1',
          '/(\W)\'"/'						=> '$1&#8216;&#8220;',
          '/"\'(\s|$)/'					=> '&#8221;&#8217;$1',
          '/(^|\s|<p>)"\'/'				=> '$1&#8220;&#8216;',
          '/"\'(\W)/'						=> '&#8221;&#8217;$1',
          '/(\W)"\'/'						=> '$1&#8220;&#8216;',

          // single quote smart quotes
          '/\'(\s|$)/'					=> '&#8217;$1',
          '/(^|\s|<p>)\'/'				=> '$1&#8216;',
          '/\'(\W)/'						=> '&#8217;$1',
          '/(\W)\'/'						=> '$1&#8216;',

          // double quote smart quotes
          '/"(\s|$)/'						=> '&#8221;$1',
          '/(^|\s|<p>)"/'					=> '$1&#8220;',
          '/"(\W)/'						=> '&#8221;$1',
          '/(\W)"/'						=> '$1&#8220;',

          // apostrophes
          "/(\w)'(\w)/"					=> '$1&#8217;$2',

          // Em dash and ellipses dots
          '/\s?\-\-\s?/'					=> '&#8212;',
          '/(\w)\.{3}/'					=> '$1&#8230;',

          // double space after sentences
          '/(\W)  /'						=> '$1&nbsp; ',

          // ampersands, if not a character entity
          '/&(?!#?[a-zA-Z0-9]{2,};)/'		=> '&amp;'
      );
    }

    return preg_replace(array_keys($table), $table, $str);
  }

  // --------------------------------------------------------------------

  /**
   * Format Newlines
   *
   * Converts newline characters into either <p> tags or <br />
   *
   * @access	public
   * @param	string
   * @return	string
   */
  function _format_newlines($str) {
    if ($str == '') {
      return $str;
    }

    if (strpos($str, "\n") === FALSE  && ! in_array($this->last_block_element, $this->inner_block_required)) {
      return $str;
    }

    // Convert two consecutive newlines to paragraphs
    $str = str_replace("\n\n", "</p>\n\n<p>", $str);

    // Convert single spaces to <br /> tags
    $str = preg_replace("/([^\n])(\n)([^\n])/", "\\1<br />\\2\\3", $str);

    // Wrap the whole enchilada in enclosing paragraphs
    if ($str != "\n") {
      $str =  '<p>'.$str.'</p>';
    }

    // Remove empty paragraphs if they are on the first line, as this
    // is a potential unintended consequence of the previous code
    $str = preg_replace("/<p><\/p>(.*)/", "\\1", $str, 1);

    return $str;
  }

  // ------------------------------------------------------------------------

  /**
   * Protect Characters
   *
   * Protects special characters from being formatted later
   * We don't want quotes converted within tags so we'll temporarily convert them to {@DQ} and {@SQ}
   * and we don't want double dashes converted to emdash entities, so they are marked with {@DD}
   * likewise double spaces are converted to {@NBS} to prevent entity conversion
   *
   * @access	public
   * @param	array
   * @return	string
   */
  function _protect_characters($match) {
    return str_replace(array("'",'"','--','  '), array('{@SQ}', '{@DQ}', '{@DD}', '{@NBS}'), $match[0]);
  }

  // --------------------------------------------------------------------

  /**
   * Convert newlines to HTML line breaks except within PRE tags
   *
   * @access	public
   * @param	string
   * @return	string
   */
  function nl2br_except_pre($str) {
    $ex = explode("pre>",$str);
    $ct = count($ex);

    $newstr = "";
    for ($i = 0; $i < $ct; $i++) {
      if (($i % 2) == 0) {
        $newstr .= nl2br($ex[$i]);
      }
      else {
        $newstr .= $ex[$i];
      }

      if ($ct - 1 != $i)
        $newstr .= "pre>";
    }

    return $newstr;
  }

}
// END Typography Class

/* End of file Typography.php */
/* Location: ./system/libraries/Typography.php */